This month, before the snow begins falling be sure to dump and clean out any planter boxes/pots and store them inside. Old planting material should be dumped onto a compost pile or taken somewhere off the property to be disposed of. Concrete planters that are too heavy to bring indoors should have as much of the potting material removed and be covered completely with tarps or covers made especially for planters, which will prevent rain or snow from settling inside and freezing.
Any moisture left inside shallow surfaces will often be subject to the expansion process of freezing/refreezing during warmer winter days and oftentimes will cause cracks to develop thus destroying the integrity of the planter.